22 · Diagnostics

Poor braking action

Make: Fiat
Model: Multipla Factory Service Manual
Year: 1998–2010
Section: Braking system › Poor braking action

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Fault diagnosisPoor braking action

POOR BRAKING ACTION

As the pressure exerted on the brake pedal increases, the braking action does not correspond.

1	CHECK WITH DIAGNOSTIC EQUIPMENT	All OK	Problems met	Operation
		Results of the tests
	Connect the diagnostic equipment (Examiner or other instruments) to the diagnostic socket Check that there are no faults in the ABS control unit.	Continue to Step 2	An error is detected in the control unit	Continue according to the instructions for the diagnostic equipment
		Continue to Step 2	Lack of dialogue with the control unit	Restore: the connection between the ABS control unit and the diagnostic connector the ABS control unit supply See E7020 ABS
2	ACTIVE DIAGNOSIS WITH DIAGNOSTIC EQUIPMENT	All OK	Problems met	Operation
	Using the diagnostic equipment (Examiner or other instruments) carry out the active diagnosis of: pump motor solenoids	Continue to Step 3	Fault detected in one solenoid	Replace electrohydraulic unit-electronic control unit Op. 3340A12
3	CHECK FRICTION SURFACES	All OK	Problems met	Operation
	Check: condition of front pad friction surfaces condition of rear pad friction surfaces	Continue to Step 4	Friction surfaces vitrified or with traces of grease, oil or water	Clean, check and eliminate the causes of the fault
			Front brake pads damaged or wrong type	Replace pads Op. 3310A60
			Rear shoes damaged or wrong type	Replace the shoes Op. 3320B10
4	CHECK FRONT DISCS AND CALIPERS	All OK	Problems met	Operation
	Check condition of front brake discs Check the condition of the brake caliper pistons	Continue to Step 5	Front discs worn or damaged	Grind the discs Op. 3310A54, or replace if necessary
		Continue to Step 5	Front caliper pistons worn or seized	Replace brake calipers Op. 3310A30
5	CHECK REAR DRUMS	All OK	Problems met	Operation
	Check the condtion of the rear brake drums. Check the condition of the rear brake cylinders.	Continue to Step 6	Rear drums worn or damaged	Replace the drums Op. 3320B30
		Continue to Step 6	Shoe control cylinders worn or seized	Replace the cylinders Op. 3320B20
6	CHECK VACUUM PIPE	All OK	Problems met	Operation
	Check condition and fitting of vacuum pipe	Continue to Step 7	Pipe fitted incorrectly or bent	Refit correctly
	Check condition and fitting of vacuum pipe	Continue to Step 7	Pipe damaged	Replace the vacuum pipe Op. 3330D24
7	CHECK NON-RETURN VALVE	All OK	Problems met	Operation
	Check that the non-return valve is working properly	Continue to Step 8	Non-return valve not working properly	Replace non-return valve Op. 3330D20
8	CHECK BRAKE SERVO	All OK	Problems met	Operation
	Check that brake servo is working properly: See Test 3330DA Check operation of brake servo	Continue to Step 9	Brake servo not working properly	Replace the servo unit Op. 3330D10
9	CHECK ENGINE VACUUM	All OK	Problems met	Operation
1.9 JTD 8V ABS	Check vacuum in vacuum circuit:	Continue to Step 10	Vacuum value incorrect	Replace brake servo vacuum unit Op. 3330D30
1.6 16v ABS		Continue to Step 10
10	CHECK BRAKE PIPES/HOSES AND BLEEDING	All OK	Problems met	Operation
	Visually check that there are no kinks or restrictions in the brake pipes, bleed the system Op. 3330A18and check that fluid emerges from the bleed screws as normal	Continue to Step 11	There are kinks or restrictions, fluid does not come out normally	Replace the section of pipe affected by the fault (see Assembly 3340B)
11	CHECKING CORRECT OPERATION	All OK	Problems met	Operation
	Check that the fault is no longer present	End of diagnosis	Fault persists	Search for the fault starting from another symptom'

As the pressure exerted on the brake pedal increases, the braking action does not correspond.

1	CHECK FRICTION SURFACES	All OK	Problems met	Operation
		Results of the tests
	Check: condition of front pad friction surfaces condition of rear pad friction surfaces	Continue to Step 2	Friction surfaces vitrified or with traces of grease, oil or water	Clean, check and eliminate the causes of the fault
			Front brake pads damaged or wrong type	Replace pads Op. 3310A60
			Rear shoes damaged or wrong type	Replace the shoes Op. 3320B10
2	CHECK FRONT DISCS AND CALIPERS	All OK	Problems met	Operation
	Check condition of front brake discs Check the condition of the brake caliper pistons	Continue to Step 3	Front discs worn or damaged	Grind the discs Op. 3310A54, or replace if necessary
		Continue to Step 3	Front caliper pistons worn or seized	Replace brake calipers Op. 3310A30
3	CHECK REAR DRUMS	All OK	Problems met	Operation
	Check the condtion of the rear brake drums. Check the condition of the rear brake cylinders.	Continue to Step 4	Rear drums worn or damaged	Replace the drums Op. 3320B30
		Continue to Step 4	Shoe control cylinders worn or seized	Replace the cylinders Op. 3320B20
4	CHECK VACUUM PIPE	All OK	Problems met	Operation
	Check condition and fitting of vacuum pipe	Continue to Step 5	Pipe fitted incorrectly or bent	Refit correctly
	Check condition and fitting of vacuum pipe	Continue to Step 5	Pipe damaged	Replace the vacuum pipe Op. 3330D24
5	CHECK NON-RETURN VALVE	All OK	Problems met	Operation
	Check that the non-return valve is working properly	Continue to Step 6	Non-return valve not working properly	Replace non-return valve Op. 3330D20
6	CHECK BRAKE SERVO	All OK	Problems met	Operation
	Check that brake servo is working properly: See Test 3330DA Check operation of brake servo	Continue to Step 7	Brake servo not working properly	Replace the servo unit Op. 3330D10
7	CHECK ENGINE VACUUM	All OK	Problems met	Operation
1.9 JTD 8V [[]	Check vacuum in vacuum circuit:	Continue to Step 8	Vacuum value incorrect	Replace brake servo vacuum unit Op. 3330D30
1.6 16v [[]		Continue to Step 8
8	CHECK BRAKE PIPES/HOSES AND BLEEDING	All OK	Problems met	Operation
	Visually check that there are no kinks or restrictions in the brake pipes, bleed the system Op. 3330A18and check that fluid emerges from the bleed screws as normal	Continue to Step 9	There are kinks or restrictions, fluid does not come out normally	Replace the section of pipe which is faulty (see Assembly 3330E)
9	CHECKING CORRECT OPERATION	All OK	Problems met	Operation
	Check that the fault is no longer present	End of diagnosis	Fault persists	Search for the fault starting from another symptom'

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Parts & tools for this job For 1998 Fiat Multipla

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